carbon cycle


: the cycle of carbon in the earth's ecosystems in which carbon dioxide is fixed by photosynthetic organisms to form organic nutrients and is ultimately restored to the inorganic state (as by respiration, protoplasmic decay, or combustion)
: a cycle of thermonuclear reactions in which four hydrogen atoms synthesize into a helium atom by the catalytic action of carbon with the release of nuclear energy and which is held to be the source of most of the energy radiated by the sun and stars

Examples of carbon cycle in a Sentence

Recent Examples on the Web Historically, climate modelers have focused on how human projects interact with the most obvious components of the carbon cycle: oceans, forests, sea ice, atmosphere, all the grand parts of the global landscape. Bathsheba Demuth, The Atlantic, 4 Jan. 2024 The water cycle, nitrogen cycle, the oxygen cycle, the carbon cycle—dust is feeding into all of these. Matt Simon, WIRED, 27 Nov. 2023 Chemical weathering can help counteract the continuous carbon dioxide released by the world’s volcanoes and is part of the Earth’s natural carbon cycle. Laura Baisas, Popular Science, 5 Oct. 2023 The geological carbon cycle also helps regulate the planet’s temperature. Laura Baisas, Popular Science, 5 Oct. 2023 By adding carbon capture and storage, that carbon cycle is broken in a positive way; and carbon dioxide is permanently removed from the biosphere before being stored safely underground. Foreign Affairs, 28 June 2023 In recent years, deforestation and wildfires have flipped the carbon cycle of the eastern Amazon basin, turning a once capacious carbon sink into a carbon emitter. Michelle Nijhuis, The New York Review of Books, 30 Mar. 2023 The carbon cycle is more complex than post posits The person in the video misunderstands the carbon cycle and makes claims that are not supported by climate research, according to Australian climate researchers and agencies. Isabella Fertel, USA TODAY, 26 July 2023 Phytoplankton are critical to making the planet livable and contribute to the global carbon cycle as key producers of oxygen. Camille Fine, USA TODAY, 28 June 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'carbon cycle.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1901, in the meaning defined at sense 1

Time Traveler
The first known use of carbon cycle was in 1901

Dictionary Entries Near carbon cycle

Cite this Entry

“Carbon cycle.” Dictionary, Merriam-Webster, Accessed 25 Feb. 2024.

Kids Definition

carbon cycle

: the cycle of carbon in living things in which carbon dioxide is used in photosynthesis to form food and growth substances and is later returned to the environment by respiration, decay, and burning

Medical Definition

carbon cycle

: the cycle of carbon in living beings in which carbon dioxide is fixed by photosynthesis to form organic nutrients and is ultimately restored to the inorganic state by respiration and protoplasmic decay

More from Merriam-Webster on carbon cycle

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